how are textures mapped to models?

Questions & Answers
1

So I’m looking at this unity example game and I’m wondering, how does unity manage to apply an image like this:

100050-vehicle-playership-orange-dff.png
100050-vehicle-playership-orange-dff.png512×512 412 KB

onto a complex 3d model, like how does it know which parts of the image go onto which polygon?

2

What you are looking for is: UV mapping. You can start reading about it from here: UV Mapping